Method and apparatus for filtered coarse pixel shading

Abstract

An apparatus and method for performing coarse pixel shading (CPS). For example, one embodiment of a method comprises: A method for coarse pixel shading (CPS) comprising: pre-processing a graphics mesh by creating a tangent-plane parameterization of desired vertex attributes for each vertex of the mesh; and performing rasterization of the mesh in a rasterization stage of a graphics pipeline using the tangent-plane parameterization.

What is claimed is: 
     
       1. A method comprising:
 pre-processing a graphics mesh by creating a tangent-plane parameterization of desired vertex attributes, wherein the tangent-plane parameterization includes:
 for each vertex of the graphics mesh,
 collecting neighboring triangles sharing the vertex, and 
 iterating over the neighboring triangles and projecting them into a same tangent plane,
 wherein the projection includes obtaining first-order derivatives at the vertex using the neighboring triangles at the tangent plane, and wherein each first-order derivative is a texture derivative that is derived based on two scalar parameters of points on the tangent plane; 
 
 
 
 performing rasterization of the graphics mesh in a rasterization stage of a graphics pipeline using the tangent-plane parameterization; and 
 displaying resulting pixels from the rasterization to a display device. 
 
     
     
       2. The method as in  claim 1  wherein pre-processing the graphics mesh further comprises:
 setting up and averaging linear attribute equations for each vertex. 
 
     
     
       3. The method as in  claim 2  wherein performing rasterization further comprises:
 setting up plane equations in a vertex shader. 
 
     
     
       4. The method as in  claim 3  wherein the plane equations comprise per-vertex tangent plane equations. 
     
     
       5. The method as in  claim 4  wherein performing rasterization further comprises:
 making the plane equations visible to a pixel shader without interpolation. 
 
     
     
       6. The method as in  claim 5  wherein performing rasterization further comprises:
 determining by the pixel shader modified texture derivatives based on a plurality of vertex tangent planes. 
 
     
     
       7. The method as in  claim 6  wherein the pixel shader further interpolates results using barycentric coordinates. 
     
     
       8. A non-transitory machine-readable medium for coarse pixel shading (CPS) having program code stored thereon which, when executed by a machine, causes the machine to perform the operations of:
 pre-processing a graphics mesh by creating a tangent-plane parameterization of desired vertex attributes, wherein the tangent-plane parameterization includes:
 for each vertex of the graphics mesh,
 collecting neighboring triangles sharing the vertex, and 
 iterating over the neighboring triangles and projecting them into a same tangent plane, wherein the projection includes obtaining first-order derivatives at the vertex using the neighboring triangles at the tangent plane, and wherein each first-order derivative is a texture derivative that is derived based on two scalar parameters of points on the tangent plane; 
 
 
 performing rasterization of the graphics mesh in a rasterization stage of a graphics pipeline using the tangent-plane parameterization; and 
 displaying resulting pixels from the rasterization to a display device. 
 
     
     
       9. The machine-readable medium as in  claim 8  wherein pre-processing the graphics mesh further comprises:
 setting up and averaging linear attribute equations for each vertex. 
 
     
     
       10. The machine-readable medium as in  claim 9  wherein performing rasterization further comprises:
 setting up plane equations in a vertex shader. 
 
     
     
       11. The machine-readable medium as in  claim 10  wherein the plane equations comprise per-vertex tangent plane equations. 
     
     
       12. The machine-readable medium as in  claim 11  wherein performing
 making the plane equations visible to a pixel shader without interpolation. 
 
     
     
       13. The machine-readable medium as in  claim 12  wherein performing rasterization further comprises:
 determining by a pixel shader modified texture derivatives based on a plurality of vertex tangent planes. 
 
     
     
       14. The machine-readable medium as in  claim 13  wherein the pixel shader further interpolates results using barycentric coordinates. 
     
     
       15. An apparatus for coarse pixel shading (CPS) comprising:
 preprocessing logic to pre-process a graphics mesh prior to rasterization by creating a tangent-plane parameterization of desired vertex attributes, wherein the tangent-plane parameterization includes:
 for each vertex of the graphics mesh,
 collecting neighboring triangles sharing the vertex, and 
 iterating over the neighboring triangles and projecting them into a same tangent plane; wherein the projection includes obtaining first-order derivatives at the vertex using the neighboring triangles at the tangent plane, and wherein each first-order derivative is a texture derivative that is derived based on two scalar parameters of points on the tangent plane, 
 
 
 a rasterization stage of a graphics pipeline to perform rasterization of the graphics mesh using the tangent-plane parameterization; and 
 a display device to display resulting pixels from the rasterization. 
 
     
     
       16. The apparatus as in  claim 15  wherein pre-processing the graphics mesh further comprises:
 setting up and averaging linear attribute equations for each vertex. 
 
     
     
       17. The apparatus as in  claim 16  wherein the rasterization stage comprises:
 a vertex shader to set up plane equations. 
 
     
     
       18. The apparatus as in  claim 17  wherein the plane equations comprise per-vertex tangent plane equations. 
     
     
       19. The apparatus as in  claim 18  wherein the rasterization stage comprises:
 a geometry shader to make the plane equations visible to a pixel shader without interpolation. 
 
     
     
       20. The apparatus as in  claim 19  wherein the rasterization stage further comprises:
 the pixel shader to determine modified texture derivatives based on a plurality of vertex tangent planes. 
 
     
     
       21. The apparatus as in  claim 20  wherein the pixel shader further interpolates results using barycentric coordinates.